The major goal of the current proposal is to obtain funds for the purchase of a Becton Dickinson FACSAria II Cell Sorter Flow Cytometer (BD-FACS) system, including a Becker BioPROtect III Bio-containment enclosure that is specifically designed for analyses on human and infectious materials. Flow cytometry is a unique and powerful technology for analyzing the phenotype and function of cells, as well as for isolating defined cell populations by sorting. In recent years, the use of flow cytometric analyses in virology research has become ever more prominent as newer approaches for dissecting the interactions between viruses and cells of the immune system have been developed. Fluorescent-based reporter systems have been developed to monitor virus replication, reactivation, and recombination, and sophisticated technological advances in instrumentation have provided new platforms for high-speed polychromatic analyses and cell sorting. In cancer and stem cell research, cell sorting by flow cytometry is the state-of-the-art method to determine and characterize the precursor cells for organ development as well as for tumor initiation, growth, and metastasis. We propose to purchase this instrument in conjunction with the Medical of Georgia (MCG) Flow Cytometry Core Facility (FACS Core). The instrument will initially support several projects of a central group of at least 18 established investigators funded by NIH grants. The needs of these projects are varied and include FACS sorting of immune cell populations from virally infected mice, and the purification of human or mouse stem cells (organ or tumor-type-specific) as well as inflammatory cell populations associated with viral infections, cancer development, and neurodegenerative diseases. The instrument will be also available to support the research projects of many other investigators at MCG, especially in procedures that require sorting of biohazardous materials. Thus, the acquisition of this cell sorter system will significantly enhance and accelerate progress in NIH-funded projects, especially those in which separation and functional analysis of cell populations from human and animal tissues exposed to pathogens (viruses) need to be analyzed. It will significantly elevate the limiting capacity of the MCG FACS facility in cell sorting of non-infectious materials due to the Core's heavy use by many investigators. We also aim to promote innovation by working with users and fostering collaborations and cross-core partnerships that encourage cutting-edge basic and translational research in infectious diseases, cancer, and neurodegenerative diseases as well as stem-cell research.